Reichsführer-SS was both a title
and a rank. The title of Reichsführer was first
created in 1926 by Joseph Berchtold. Berchtold's predecessor,
Julius Schreck, never referred to himself as Reichsführer
but the title was retroactively applied to him in later
years. In 1929, Heinrich
Himmler became Reichsführer-SS and referred
to himself by his title instead of his regular SS rank.
This set the precedent for the Commanding General of
the SS to be called Reichsführer-SS.